(a) Field of the Invention
The present invention relates to a liquid crystal display having a wide viewing angle, and more particularly, to a liquid crystal display in which a viewing angle of the same is made wide by patterning apertures in electrodes.
(b) Description of the Related Art
Liquid crystal displays (LCDs) typically include two substrates and a liquid crystal layer interposed between the substrates. The transmittance of light is controlled by the intensity of an electric field applied to the liquid crystal layer.
A vertically aligned twisted nematic (VATN) mode LCD has two transparent substrates each having transparent electrodes, a liquid crystal material interposed between the two substrates, and two polarizing films attached to the outside surfaces of the two substrates. In the absence of an electric field, liquid crystal molecules take on a homeotropic orientation in which the long axes of the molecules are perpendicular to the substrates. If an electric field is applied between the substrates, the liquid crystal molecules are aligned parallel to the substrates and are twisted helically to take on a pitch.
In a VATN mode LCD, liquid crystal molecules take on a homeotropic orientation in which the long axes of the molecules are perpendicular to the substrates. With this configuration, light is cut off almost completely in an xe2x80x9coffxe2x80x9d state when an electric field above a certain value is not applied to a liquid crystal layer that is sandwiched between two polarizing films whose polarizing axes are perpendicularly oriented. In the normally black mode, since brightness in the off state is extremely low, a significantly higher contrast ratio can be obtained when compared to the contrast ratio of conventional twisted nematic LCDs. However, light retardation is greatly changed according to a viewing direction. Therefore, VATN mode LCDs also have the same problem of narrow viewing angles as does the conventional twisted nematic LCDs.
To solve this problem, many methods of patterning electrodes and the use of a skewed field to form multi-domain regions have been proposed. In U.S. Pat. No. 5,309,264, Lien disclosed a method of forming xe2x80x9cXxe2x80x9d-shaped apertures on the transparent electrodes of one of the two substrates. In U.S. Pat. No. 5,434,690, there is also disclosed a method of forming apertures on transparent electrodes of both of the two substrates by turns.
However, to apply above described methods, another photolithography step is needed to pattern a common electrode. If color filters are exposed to liquid crystal material, pigments of the color filters may affect to the liquid crystal material. To prevent this problem from occurring, an overcoating layer should be formed on the color filters. Furthermore, serious light leaks from around the boundaries of the apertures can occur.
The present invention has been made in an effort to solve the above problems.
It is an object of the present invention to provide a liquid crystal display having a wide viewing angle.
To solve the above problems, the present invention provides a multi-domain LCD of which color filters have grooves and common electrodes are formed on the color filters.
A black matrix may also be formed to overlap the grooves to prevent light leakage.
Pixel electrodes formed on a thin film transistor array panel may have an aperture. In this case, if the aperture and the color filter grooves are alternately arranged in a parallel manner, a wide viewing angle and a stable alignment of liquid crystal molecules are achieved.
Additionally, if the indium-tin-oxide (ITO) is thinly deposited twice to form the common electrode, a disconnection of the common electrode around the groove is prevented.